Apparatus and methods for increasing energy efficiency of pumped refrigerant cooling systems

ABSTRACT

An economizer module for increasing energy efficiency of a pumped refrigerant cooling system is connected to a refrigerant pumping unit including a primary pump connected with heat extractor(s) via a primary circuit and a primary heat exchanger connected with a condensing unit via a secondary circuit. The economizer module includes a control panel with control software, a secondary heat exchanger connected with the heat extractor(s) via the primary circuit and with the primary heat exchanger, a cooler connected with the secondary heat exchanger via an economizer circuit, and a secondary pump connected between the cooler and the secondary heat exchanger. The control panel executes the control software to control fluid flow in the economizer circuit via the secondary pump so as to use ambient air to reject heat from working fluid being used to collect heat from refrigerant in said primary circuit before said heat travels to said secondary circuit.

BACKGROUND OF THE INVENTION

The present invention generally relates to apparatus and methods for cooling electronic devices. More particularly, the present invention relates to apparatus and methods for cooling heated air emanating from, or entering, electronic equipment to prevent overheating thereof.

Various approaches have been suggested for cooling electronic equipment and rooms. All of these approaches require energy in order to remove heat. One such approach involves utilizing a Refrigerant Pump in order to distribute refrigerant to heat extractors which transfer heat from the air into the refrigerant. This heat is then carried outside by a Secondary Circuit working fluid where it is finally removed either by a water chiller or by a refrigerant-based direct expansion condensing unit.

Energy economization systems in various forms have emerged in order to reduce the amount of energy, and the accompanying energy costs and environmental impact that traditional Secondary Circuit cooling equipment requires.

SUMMARY OF THE INVENTION

The present invention introduces an independent Economizer Circuit connected to the Refrigerant Pump which can be used in combination with traditional cooling equipment, including those with other economization systems, for better energy efficiency.

The present invention uses ambient air to reject heat from a working fluid being used to collect heat from the Primary Circuit refrigerant before said heat travels to the Secondary Circuit. This Pumped Refrigerant Economizer System approach reduces the heat load that would otherwise be mitigated by the Secondary Circuit equipment, thereby reducing the amount of energy required to reject said heat load through traditional means (See FIG. 1).

In a preferred embodiment, said System utilizes a dry cooler, which consists of a standard condenser coil coupled with fans to draw ambient air across the coil, and glycol/water as the working fluid which is pumped using a standard variable or fixed speed water pump.

In a preferred embodiment, the present invention utilizes the dry cooler with water pump to deliver cooled glycol/water to a Secondary Heat Exchanger, as shown in FIG. 1, located inside the Refrigerant Pump where heat collected in the Primary Circuit can be transferred to said glycol/water, and then rejected back to outside air at the dry cooler. The Secondary Heat Exchanger may alternatively be located outside of the Refrigerant Pump, either inside or outside of the physical building space data center (e.g., a computer server warehouse) with insulated refrigerant lines as applicable.

The dry cooler discussed above may be used in cooler climates with low average temperatures, however new adiabatic cooling technologies have allowed coolers to work effectively in warmer ambient temperatures as well. Since this equipment does not require compressors, it uses significantly less energy to run than compressor-based technologies. This Economizer Circuit uses glycol/water in the preferred embodiment, however any working fluid may be used.

The present invention may utilize any substitute device that is able to reject collected heat from Secondary Heat Exchanger from the working fluid and then return said cooled fluid to Secondary Heat Exchanger as shown in FIG. 1.

In the embodiment shown in FIG. 1, the present invention combines the dry cooler with a variable speed water pump, a check valve, and a condenser heat exchanger (Secondary Heat Exchanger) which is piped to the return connection of the Primary Heat Exchanger of the Refrigerant Pump.

Additional preferred sensors include a refrigerant temperature sensor to measure return refrigerant temperature, and water temperature sensors to measure the supply and return glycol/water temperatures from the dry cooler. Temperature measurements from the glycol/water temperature sensors may be used to evaluate performance and operation of the Economizer Circuit.

In the case of a variable speed water pump, the water pump speed is commanded by the control software in the control panel of the Economizer Module, as shown in FIG. 2, or of the Refrigerant Pump, in order to increase or decrease water flow as required to reduce the measured error between the target refrigerant temperature setpoint and the measured refrigerant temperature. In the case of a fixed speed water pump, at least one water control valve may be used in order to adjust the glycol/water flow in the Economizer Circuit.

In a more complex embodiment, the dry cooler and water pump described above may provide sufficient water flow and capacity to service multiple Refrigerant Pumps rather than just one. In this case, electronically adjustable water valves may be introduced at each individual Refrigerant Pump in order to control the water flow to each individual Refrigerant Pump. Like the water pump, these water valves may be commanded by the control software of the Economizer Module, as shown in FIG. 2, or of the Refrigerant Pump, in order to increase or decrease water flow as required to reduce the measured error between the target refrigerant temperature setpoint and the measured refrigerant temperature. Additional devices, such as differential pressure regulators, may also be required for proper pressure and fluid flow control.

All software controls previously discussed for control of the water pumps and/or water valves may be substituted by mechanical or electromechanical devices as applicable.

As shown in a preferred embodiment in FIG. 2, the Economization Module which includes the condenser heat exchanger that will be providing system economization, may be modular in nature and able to be installed as an add-on device to existing, non-specific pumped refrigerant systems.

In a preferred embodiment, this Economizer Module may be installed at or vertically above the return connection of the Primary Heat Exchanger in the Refrigerant Pump shown in FIG. 1, in order for gravity to aid in the return and circulation of refrigerant. However, the module may also be installed below said return connection with the help of additional devices and/or methods able to aid in the return and circulation of refrigerant.

Other objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, embodiments of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will further be described, by way of example, with reference to the accompanying drawings:

FIG. 1 is a graphic representation of a pumped refrigerant cooling system including an economizer module according to an embodiment of the invention;

FIG. 2 is a perspective view of the economizer module according to an embodiment of the invention; and

FIG. 3 is a perspective view of the pumped refrigerant cooling system including the economizer module according to an embodiment of the invention.

DETAILED DESCRIPTION

Referring to FIGS. 1, 2 and 3, the present invention introduces an independent Economizer Module/Circuit connected to the Refrigerant Pump which can be used in combination with traditional cooling equipment, including those with other economization systems, for better energy efficiency.

As shown in FIGS. 1 and 3, a pumped refrigerant cooling system 100 includes a refrigerant pumping unit 10 (also referred to as refrigerant pump 10) having a primary heat exchanger 12. The refrigerant pumping unit 10 also includes a tank 16 connected with primary heat exchanger 12, and a primary pump 18 connected with tank 16, as shown in FIG. 1. The pumped refrigerant cooling system 100 also includes one or more heat extractor(s) 20 (also referred to as evaporator network 20). The primary pump 18 of refrigerant pumping unit 10 is connected to heat extractor(s) 20 via a primary circuit 25. The pumped refrigerant cooling system 100 also includes a condensing unit 30 (also referred to as water chiller 30). The primary heat exchanger 12 of refrigerant pumping unit 10 is connected to condensing unit 30 via a secondary circuit 35.

According to an aspect of the present invention, pumped refrigerant cooling system 100 further includes an economizer module 40 (also referred to as pumped refrigerant economizer system 40) having a secondary heat exchanger 42 (also referred to as condenser heat exchanger 42) incorporated therein. The economizer module 40 also includes a cooler 50 (also referred to as dry cooler 50, adiabatic chiller 50, or geothermal cooling 50). The cooler 50 is connected to secondary heat exchanger 42 via an economizer circuit 55.

As shown in FIGS. 1 and 3, economizer module 40 (also referred to as pumped refrigerant or glycol/water economizer system 40) includes secondary heat exchanger 42, cooler 50, and secondary pump 58 connected between cooler 50 and secondary heat exchanger 42, which are connected via economizer circuit 55. The economizer module 40 utilizes cooler 50 with secondary pump 58 to deliver cooled working fluid to secondary heat exchanger 42. Although economizer module 40 uses glycol/water as the working fluid according to example embodiments described herein, it should be appreciated that any other suitable working fluid may be used in economizer circuit 55.

In some example embodiments, the secondary (condenser) heat exchanger 42 of economizer module 40 may be located inside refrigerant pumping unit 10, as shown in FIG. 1, where heat collected in primary circuit 25 can be transferred to said glycol/water, and then rejected back to outside air at cooler 50. However, in some other example embodiments, the secondary (condenser) heat exchanger 42 may be located outside of (external to) refrigerant pumping unit 10, such as either inside or outside of the data center, with insulated refrigerant lines connecting secondary heat exchanger 42 to refrigerant pumping unit 10. These alternative example embodiments are indicated using dashed lines in FIG. 1.

In some example embodiments, the cooler 50 may be a dry cooler, which includes a standard condenser coil coupled with fans to draw ambient air across the coil, and glycol/water as the working fluid which is pumped using the secondary pump 58, which may be a standard variable or fixed speed water pump, for example. Utilizing a dry cooler as cooler 50 may be used in cooler climates with low average temperatures.

However, in some other example embodiments, the cooler 50 may be an adiabatic chiller (instead of a dry cooler). Utilizing adiabatic cooling technologies to implement cooler 50 may allow the cooler 50 to work effectively in warmer ambient temperatures as well as colder temperatures, and may also use significantly less energy to run than compressor-based technologies, since adiabatic chiller equipment does not require compressors.

In yet some other example embodiments, the cooler 50 may be implemented using geothermal cooling techniques. This process works like the dry cooler, except instead of cooling fans, piping is sent below the surface of the ground and the earth itself is used as a heat sink. It should also be appreciated that the economizer module 40 may utilize any substitute device for cooler 50 (other than the three examples mentioned above) that is able to reject collected heat from secondary heat exchanger 42 from the working fluid, and then return said cooled working fluid to secondary heat exchanger 42, as shown in FIG. 1.

As shown in FIG. 2, economizer module 40 may include a control panel 41, a condenser heat exchanger 42 (the secondary heat exchanger 42), a refrigerant return 43, a glycol/water outlet 44, a glycol/water inlet 45, and a connection to refrigerant pump return 46. The secondary heat exchanger 42 may be connected to heat extractor(s) 20 of primary circuit 25 via refrigerant return 43, connected to cooler 50 (and optionally control valve 59) of economizer circuit 55 via glycol/water outlet 44, connected to cooler 50 and secondary pump 58 of economizer circuit 55 via glycol/water inlet 45, and connected to the return of primary heat exchanger 12 of refrigerant pumping unit 10 via connection to refrigerant pump return 46. Other suitable arrangements or modified configurations for these inlets/outlets/connections are also possible in some other example embodiments. Although not shown in FIG. 2, it should be appreciated that control panel 41 may include a memory device for storing the control software and a processor configured to execute the control software to implement methods, processes, and/or steps according to example embodiments described herein.

As shown in FIG. 1, economizer module 40 includes secondary pump 58 connected between cooler 50 and secondary heat exchanger 42 (the condenser heat exchanger 42) in economizer circuit 55. In some example embodiments, economizer module 40 may further include a check valve 59 (also referred to as a water control valve 59 or PIVC 59) connected between secondary heat exchanger 42 and cooler 50 in economizer circuit 55, as shown in FIG. 1. Inclusion of a check valve or control valve 59 in economizer module 40 may be considered optional (as indicated with dashed lines in FIG. 1), and may depend on whether secondary pump 58 is a fixed speed pump or a variable speed pump, for example.

Thus, according to the example embodiment shown in FIG. 1, the present invention incorporates an independent economizer module/circuit (40/55) that combines a cooler 50 (e.g., a dry cooler 50) with a secondary pump 58 (e.g., a variable speed water pump 58), an optional check valve 59 (e.g., water control valve 59), and a secondary heat exchanger 42 (e.g., condenser heat exchanger 42), which is piped to the return connection of primary heat exchanger 12 of refrigerant pumping unit 10.

Although not shown in the figures, additional preferred sensors may include a refrigerant temperature sensor configured to measure return refrigerant temperature, and water temperature sensors configured to measure the supply and return glycol/water temperatures to and from cooler 50. Temperature measurements from the glycol/water temperature sensors may be used to evaluate performance and operation of economizer module 40 (and/or economizer circuit 55), and dynamically make any adjustments if needed.

In the case of a variable speed water pump being used as secondary pump 58 of economizer module 40, the water pump speed is commanded by the control software in the control panel 41 of the economizer module 40, as shown in FIG. 2, or of the refrigerant pumping unit 10, in order to increase or decrease glycol/water flow as needed to reduce a measured error between a target refrigerant temperature setpoint and a measured refrigerant temperature. In the case of a fixed speed water pump being used as secondary pump 58 of economizer module 40, at least one water control valve 59 may optionally be used in order to adjust the glycol/water flow in economizer circuit 55 (see FIG. 1).

According to a more complex embodiment, cooler 50 and secondary pump 58 described above may provide sufficient water flow and capacity to service multiple refrigerant pumps, rather than just a single refrigerant pumping unit 10. In this case, multiple electronically adjustable water valves (not shown in figures) may be introduced at each individual refrigerant pumping unit 10 in order to control the glycol/water flow to each individual refrigerant pump 10, respectively. Like with secondary pump 58 and/or control valve 59, each of these water valves may be commanded by the control software of economizer module 40 (via control panel 41), as shown in FIG. 2, or of each individual refrigerant pump 10, in order to increase or decrease glycol/water flow as needed to reduce the measured error between the target refrigerant temperature setpoint and the measured refrigerant temperature. In some example embodiments, one or more additional devices, such as differential pressure regulators (not shown in figures), may also be utilized to ensure proper pressure and working fluid flow control in the case of a single economizer module 40 servicing multiple refrigerant pumps 10.

Although example embodiments described above incorporate software controls for control of the water pumps and/or water valves (e.g., control software stored in a memory and executed by a processor of control panel 41 of FIG. 2), it should be appreciated that one or more suitable mechanical or electromechanical devices may be substituted for the software controls, as applicable. Therefore, example embodiments of the present invention are not limited to the computerized software-based implementation described herein.

As shown in FIG. 2, the economizer module 40, which includes the secondary (condenser) heat exchanger 42 that will be providing system economization, may be modular in nature and able to be installed as an add-on device to existing, non-specific pumped refrigerant systems.

In a preferred embodiment, economizer module 40 may be installed at or vertically above the return connection of primary heat exchanger 12 in refrigerant pumping unit 10 shown in FIGS. 1 and 3, in order to allow gravity to aid in the return and circulation of refrigerant. However, economizer module 40 may alternatively be installed below said return connection, with the help of one or more additional devices (not shown in figures) and/or methods that are able to aid in the return and circulation of refrigerant.

According to various example embodiments described above, the present invention incorporates an independent Economizer Module/Circuit (40, 55, etc.) that uses ambient air to reject heat from a working fluid (e.g., glycol/water) being used to collect heat from the Primary Circuit refrigerant (e.g., primary circuit 25 and heat extractor(s)/evaporator network 20), before said heat travels to the Secondary Circuit (e.g., secondary circuit 35 and condensing unit/water chiller 30). This Pumped Refrigerant Economizer System approach reduces the heat load that would otherwise be mitigated by the Secondary Circuit equipment, thereby reducing the amount of energy required to reject said heat load through traditional means (See FIG. 1).

Although the invention has been described with reference to example embodiments thereof, it is understood that various modifications may be made thereto without departing from the full spirit and scope of the invention as defined by the claims which follow. 

What is claimed is:
 1. An economizer module for increasing energy efficiency of a pumped refrigerant cooling system, wherein the economizer module is connected to a refrigerant pumping unit of the pumped refrigerant cooling system, wherein the refrigerant pumping unit includes a primary pump connected with one or more heat extractor(s) via a primary circuit and a primary heat exchanger connected with a condensing unit via a secondary circuit, the economizer module comprising: a control panel including a processor and a memory storing control software; a secondary heat exchanger connected with the one or more heat extractor(s) via the primary circuit, and connected with a return of the primary heat exchanger of the refrigerant pumping unit; a cooler connected with the secondary heat exchanger via an economizer circuit; and a secondary pump connected between the cooler and the secondary heat exchanger in the economizer circuit, wherein the processor of the control panel is configured to execute the control software to control fluid flow to and from the cooler in the economizer circuit via the secondary pump so as to use ambient air to reject heat from a working fluid being used to collect heat from refrigerant in said primary circuit before said heat travels to said secondary circuit.
 2. The economizer module of claim 1, wherein controlling the secondary pump associated with the economizer circuit so as to reject heat from the working fluid via the cooler reduces the heat load that would otherwise be mitigated by the condensing unit associated with the secondary circuit that is connected to the primary heat exchanger of the refrigerant pumping unit.
 3. The economizer module of claim 1, wherein the economizer module utilizes a dry cooler as the cooler associated with the economizer circuit, wherein the dry cooler includes a condenser coil coupled with fans to draw the ambient air across the condenser coil, and wherein the secondary pump is a water pump, and the economizer module utilizes glycol/water as the working fluid, which is pumped using the water pump according to the control software.
 4. The economizer module of claim 3, wherein the economizer module utilizes the dry cooler with the water pump to deliver cooled glycol/water to the secondary heat exchanger.
 5. The economizer module of claim 4, wherein the secondary heat exchanger of the economizer module is located inside the refrigerant pumping unit, where heat collected in the primary circuit can be transferred to said glycol/water and then rejected back to outside air at the dry cooler.
 6. The economizer module of claim 4, wherein the secondary heat exchanger of the economizer module is located outside the refrigerant pumping unit, with insulated refrigerant lines connecting the secondary heat exchanger to the primary heat exchanger of the refrigerant pumping unit.
 7. The economizer module of claim 1, wherein the economizer module utilizes one of a dry cooler, an adiabatic chiller, or geothermal cooling as the cooler to reject collected heat from the secondary heat exchanger from the working fluid and then return cooled working fluid to the secondary heat exchanger.
 8. The economizer module of claim 1, wherein the economizer module further includes a check valve connected between the secondary heat exchanger and the cooler in the economizer circuit, and the processor of the control panel is configured to execute the control software to control the check valve to adjust the flow of working fluid to and from the cooler in the economizer circuit.
 9. The economizer module of claim 1, wherein the secondary heat exchanger of the economizer module is piped to a return connection of the primary heat exchanger of the refrigerant pumping unit.
 10. The economizer module of claim 9, wherein the economizer module further includes a refrigerant temperature sensor configured to measure return refrigerant temperature, and glycol/water temperature sensors configured to measure supply and return glycol/water temperatures to and from the cooler.
 11. The economizer module of claim 10, wherein the processor of the control panel is configured to execute the control software to evaluate performance and operation of the economizer module or economizer circuit based on the temperature measurements from the glycol/water temperature sensors.
 12. The economizer module of claim 11, wherein the secondary pump of the economizer module is a variable speed water pump, and wherein the water pump speed is commanded by the control software in the control panel of the economizer module in order to increase or decrease glycol/water flow in the economizer circuit as needed to reduce a measured error between a target refrigerant temperature setpoint and a measured refrigerant temperature.
 13. The economizer module of claim 11, wherein the secondary pump of the economizer module is a fixed speed water pump, wherein the economizer module further includes at least one water control valve between the secondary heat exchanger and the cooler in the economizer circuit, and wherein the processor of the control panel is further configured to execute the control software to control the at least one water control valve so as to increase or decrease glycol/water flow in the economizer circuit as needed to reduce a measured error between a target refrigerant temperature setpoint and a measured refrigerant temperature.
 14. The economizer module of claim 11, wherein the cooler and the secondary pump of the economizer module provide sufficient water flow and capacity to service a plurality of refrigerant pumps including the refrigerant pumping unit and one or more additional refrigerant pumping units, wherein each individual refrigerant pumping unit further includes an electronically adjustable water control valve configured to control fluid flow to said refrigerant pumping unit, respectively, and wherein the processor of the control panel is further configured to execute the control software to control the electronically adjustable water control valve of each individual refrigerant pump in order to increase or decrease glycol/water flow as needed to reduce a measured error between a target refrigerant temperature setpoint and a measured refrigerant temperature.
 15. The economizer module of claim 14, wherein the economizer module further includes one or more differential pressure regulators configured to control pressure and fluid flow for each individual refrigerant pumping unit, respectively.
 16. The economizer module of claim 9, which includes the secondary heat exchanger that provides pumped refrigerant cooling system economization, is modular and installable as an add-on device to existing, non-specific pumped refrigerant systems.
 17. The economizer module of claim 16, wherein the economizer module is installed at or vertically above the return connection of the primary heat exchanger in the refrigerant pumping unit, to allow for gravity to aid in the return and circulation of refrigerant.
 18. The economizer module of claim 16, wherein the economizer module is installed below the return connection of the primary heat exchanger in the refrigerant pumping unit, and wherein the economizer module further includes a device that is configured to aid in the return and circulation of refrigerant. 